1. Field of the Invention
This invention relates to a manually operated fluid flow control valve that has especial, but not exclusive, use as a manually-operated drain valve for a compressed air filter.
2. The Prior Art
Compressed air filters conventionally include a bowl, usually made of strong transparent material such as a polycarbonate, in which filtered-out liquid, principally water, and particulate foreign bodies collect during the passage of compressed air through the filter. The collected liquid and foreign bodies are periodically drained off by an automatic drain valve or a manually-operated ("manual") drain valve fitted to the base of the bowl. Hitherto, manual drain valves have conventionally been sealingly secured to the bowl by a threaded nut connection which entails significant assembly time. Further, in order fully to open the usual type of manual drain valve, it is necessary to rotate the valve member through several revolutions, which can be somewhat inconvenient.
It is one object of the present invention to provide a manually-operated drain valve suitable, for example, for use in a compressed air filter, which can, in a preferred embodiment, be readily connected, without the use of a screwed fastener, to the bowl of such a filter.
An additional or alternative object of the invention is to provide such a drain valve which is of the "quarter turn" type, that is to say one which can be moved from a fully closed position to a fully open one, and vice versa, simply by manually rotating an actuator of the valve through about 90.degree..